Cyborg has just upgraded Titans Tower with a number of high-tech, but non-essential paraphernalia and is proudly presenting them to his friends when he suddenly vanishes from the face of the Earth with a lightning zap. In fact, Cyborg finds himself stranded 5,000 years before his time, right in the middle of a battle between a barbarian horde and an army of green-glowing slime monsters!At first all Cyborg wants is to keep out of the way, in fear that any action on his part may alter the future, but when he sees one of the warriors about to be finished by his opposition, he interferes and saves the warrior's life. Subsequently, he ends up defeating all the monsters single-handedly, though the excessive use of his sonic cannon leaves him with little spare power. To top off the night, the warrior he rescued turns out to be a woman by the name of Sarasim, the leader of the barbarian tribe.
Cyborg is welcomed into the tribe with open arms, but he is reluctant to stay, both because this is not his time and that he has no means of recharging himself. Not understanding all he says, Sarasim declares Cyborg the champion of her people and gives him a sword as a sign of his status. This happens much to the chagrin of a warrior named Krall, who had repeatedly tried to kill at least one of the monsters but failed miserably. It soon transpires that Krall is in fact the instigator behind the monsters' attack: He had woken a witch from a cursed sleep to use her power to establish himself as the champion of his people. But the witch, unwilling to serve him, has twisted his every command as a subtle way of rebellion against him. It was also her magic that had dragged Cyborg into this time after Krall had ordered her to send him the strength to defeat the monsters. Enraged over his failure, Krall commands the witch to remedy the situation.
The next day, Cyborg unsuccessfully tries to recharge his batteries with a kit-bashed dynamo when Sarasim visits him. She gives him a tour through her village to convice him to stay; Cyborg remains reluctant, but he slowly comes to care for Sarasim and her people. The same evening, the witch's monsters attack, crashing like meteorites inside the village's perimeter. Outnumbered and surprised, the villagers face certain doom until Cyborg breaks the dam which blocks the nearby river, flooding the creatures and dissolving them. Once again he is hailed as the village's hero, but he cannot join their merryment.Once alone, Cyborg is approached by Krall, who takes him to the witch. The witch opens a magical portal which would send Cyborg back to his own time, but just as he prepares to step through, he realizes that Krall is behind the monster attacks and refuses to leave Sarasim to his mercy. Krall attacks him but finds himself outmatched, and asks the witch for more power. The witch responds by having several of his minions merge with Krall, turning him into a monster. With more than enough strength, Krall brings Cyborg down, spears his power cell and casts him into the river to drown. Cyborg reawakens to find Sarasim standing over him and with some of his power restored by a water-driven generator based on his dynamo design. Cyborg loses no time telling her about Krall's treachery, and now fully determined to stay, he helps her people prepare for the upcoming battle.
As night falls, Krall and his army of minions attack the village. While the monsters keep Cyborg busy, Krall singles out Sarasim and mercilessly batters her to the ground. Cyborg activates his sonic cannon and channels all his power into it, but before he can fire the shot, he is pulled back into his own time by Raven's magic. He frantically tries to make her return him, but the magic only worked one way.
Dejected, Cyborg returns to his quarters, where Raven soon visits him with a book. The volume turns out to be a chronicle about the history of Sarasim's tribe, from which Cyborg learns to his joy and relief that Sarasim had managed to kill Krall after all. He was still remembered by the tribe as their greatest hero: In an accompanying illustration Cyborg is depicted without his implants and armor, a testimony of the tribe's appreciation of his selfless bravery.
- Beast Boy: Okay. Before anybody says anything, that was totally not my fault!
- Cyborg: Don't do anything, don't touch anything! Sci-fi Rule number one: You start messing with the past, you end up with monkeys ruling the future!
- Cyborg: Monkeys or not, it's time someone went Bronze Age on your butt!
- Cyborg: Sarasim...if this doesn't go well, there's something I need to tell you. Something I should've said before.
Sarasim: [after kissing him] You already have.
- Raven: [after Cyborg commenting on working on the toaster] Evil beware. We have waffles.
- Sarasim: To arms! Prepare for battle!
Cyborg: Wait! Your armor!
Sarasim: A true warrior doesn't need armor.
- The "monkeys ruling the future" line is a reference to the classic sci-fi apocalypse series Planet of the Apes.
- The video game sequence is a parody of the classic arcade game Frogger.